Decontamination by means of ultra violet (UV) light is a well-established and reliable technique for use in systems for purifying fluids, in particular systems suitable for providing potable water. These systems are efficient and perform satisfactorily without the use of chemicals. Traditionally, germicidal UV light is produced with mercury lamps. These lamps are effective, but are bulky, rather fragile, require significant maintenance and pose a disposal issue.
Cited drawbacks are at least alleviated by employing light emitting diodes (LEDs) as light sources in purification systems of the above kind. UV LEDs of these systems emit a conventional light cone with an intensity pattern that approximates a Gaussian curve. Systems having LEDs of this kind are employed to attack the DNA of micro-organisms that contaminate the fluid, typically water, whereby the emitted UV-radiation destroys their genetic information and eliminates their reproductive capability thus making them harmless.
In this context and as is known in the art, the morphology and the aggregation properties of the different species of microorganisms vary greatly. Accordingly, E. coli-bacteria are rod-shaped and gather in a relatively large, irregularly-shaped clusters. Staphylococci, on the other hand, are substantially spherical and aggregate in grape-like clusters while Streptococci normally group in pairs or in chains. Spiral-shaped bacteria are also known. Moreover, clusters of bacteria present in the running fluid are randomly oriented in the fluid. In addition, each bacteria species has its DNA-string in a specific place in the cell—this is at least partially conditioned by the shape of the particular species. A light-emitting device, the purpose of which is to completely destroy the metabolic activity, mainly the DNA of the bacteria, or other microorganisms, needs to be designed with the above in mind.
US2012/0138545 discloses a system for fluid purification using UV LEDs. The system comprising at least one LED is preinstalled in a pipe or a faucet, i.e. the system is fixedly attached to the inner surface of the pipe/faucet at the factory. Given the apparent difficulties as regards the accessibility of the system, the replacement of the system at hand is a very challenging task, requiring considerable time and effort. Moreover, placement of the diodes themselves, either within the fluid flow or radially protruding from the pipe wall, renders the individual diodes more sensitive to external circumstances. More specifically, elevated fluid flow in the pipe might induce wear in the platform that supports the diode(s) or downright break it. Also, turbidity-causing particles being carried by the fluid flowing in the pipe might soil the light emitting area of the exposed diode such that its functionality is lost.
An objective of the present invention is therefore to reduce at least some of the drawbacks associated with the current art.